Box-board



UNITE STATES PATENT OFFICE.

CHARLES A. BROWN, ELIAS B. DENISON, AND CHARLES D. "BROWN, OF

t PORTLAND, MAINE.

BOX-BOARD.

SPECIFICATION forming part of Letters Patent No. 289,383, dated December 4, 1883. Application filed August 6, 1883. (N0 specimens.)

I cheaply made; that it should be of a light color and possess considerable strength. WVood pulp made by simply grinding the wood will produce a board of nearly the same color as the wood itself, and therefore by using wood of a light color pulp may be obtained of a desirable color for box-board. It will, however, if made from the varieties of wood usually employed, lack the strength which is desirable.

It is well known that if woodis steamed or boiled for a considerable time before it is :ground a pulp is obtained without much increase in expense which will make a much stronger board, but of a darker color, than that obtained from wood treated.

To secure a gain in strength without the dark color and without much increase in cost is the object of our invention. We secure of the same kind not so these results by combining in the process of making the board one or more layers of dark pulp from steamed or boiled wood with one or more layers of light-colored unsteamed or unboiled wood, the latter giving a surface of desirable color, while the former gives a greatof light color, the layer of steamed or boiled pulp will be laid between the layers of light color; but if only one surface is to be of light color the other surface will be made by a layer of the steamed or boiled pulp.

We are aware that paper has been made with a surface of manila applied to a body of ground woodpulp, and of ordinary coarse and dark straw pulp with a surface of ground wood pulp; and also of bleached manila pulp combined with unbleached manila pulp.

\rVe claim- Box-board made from ground wood pulp, steamed or boiled, with ground wood pulp unsteamed applied to its surface, substantially as described.

CHAS. A. BROWN. ELIAS B. DENISON. CHARLES D. BROWN.

Witnesses:

FRANKLIN O. PAYSON, HENRY S. PAYSON. 

